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Dispersive liquid-liquid microextraction followed by high-performance liquid chromatography as an efficient and sensitive technique for determination of nandrolone and testosterone in human urine

Rezaee Mohammad

Acta Chromatographica

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2023

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Vol. 35, no. 1

28--34

EN

Dispersive liquid-liquid microextraction (DLLME) and high performance liquid chromatography – UV detection was presented for extraction and determination of nandrolone and testosterone in human urines. Chloroform at microliter volume level and acetonitrile were used as extraction and dispersive solvents, respectively. The main advantages of method are high speed, high enrichment factor, high recovery, good repeatability and extraction solvent volume at µL level. The influence of several variables (e.g. type and volume of disperser and extraction solvents, ionic strength, etc.) on the performance of the sample preparation step was carefully evaluated. Under the optimum conditions, the calibration graphs were linear in the range of 5–500 μg L⁻¹ with detection limit of 2.5 μg L⁻¹ for both of them. The relative standard deviation (R.S.D.s) for five replicate measurements of nandrolone and testosterone were 9.4% and 8.8%, respectively. The relative recoveries of nandrolone and testosterone in urine sample at spiking level of 25.0 μg L⁻¹ are ranged between 86.4% and 98%. DLLME combined with HPLC-UV is a fast, simple and efficient method for the determination of nandrolone and testosterone in human urines.

2

Development of ultrasound-assisted extraction followed by solid-phase extraction followed by dispersive liquid–liquid microextraction followed by gas chromatography for the sensitive determination of diazinon in garden parsley as vegetable samples

Rezaee Mohammad, Khalilian Faezeh, Pourjavid Mohammad Reza

Acta Chromatographica

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2023

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Vol. 35, no. 4

347--353

EN

A new pretreatment method termed ultrasound-assisted extraction (UAE) which is combined with solid-phase extraction which is combined with dispersive liquid-liquid microextraction (SPE-DLLME) followed by gas chromatography-flame ionization detector (GC-FID) analysis has been developed for the determination of diazinon in garden parsley as vegetable samples. The analyte was extracted from garden parsley sample using ultrasound-assisted extraction followed by solid-phase extraction followed by dispersive liquid-liquid microextraction. Various parameters that affect the efficiency of the extraction techniques have been optimized. The calibration plot was linear in the range of 5.0–1,000 μg kg⁻¹ with detection limit of 1.0 μg kg⁻¹ for diazinon in garden parsley samples. The results confirm the suitability of the UAE-SPE-DLLME-GC-FID as a sensitive method for the analysis of the targeted analyte in garden parsley samples.

3

Cyclodextrin-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplets coupled with HPLC for the determination of pyrethroid residues in cereals

Jiang Haijuan, Bi Xinyuan, Huang Xin, Guo Xingle, Zou Ziyu, Li Ying, Jing Xu, Wu Junxue

Acta Chromatographica

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2023

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Vol. 35, no. 1

21--27

EN

A simple, rapid, and environmentally friendly sample preparation method for pyrethroids determination in cereals using cyclodextrin-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplets coupled with high-performance liquid chromatography was established. The cereal samples were extracted with acetonitrile, cleaned up, and concentrated by green extractant menthol via γ-cyclodextrin assisted extraction process. The extractant menthol dispersed as fine droplets in the cyclodextrin solution and then solidified at room temperature for efficient extraction and convenient collection. The optimized method provided good linearity in the range of 0.01–10 mg kg⁻¹ with limits of detection of 3.5–9.5 μg kg⁻¹. The fortified recoveries of three pyrethroids (i.e., lambda-cyhalothrin, deltamethrin, and bifenthrin) in four cereals (i.e., rice, wheat, maize, and millet) at three levels were in the range of 77.6–101.6% with relative standard deviations of 0.6–6.6%. Overall, the proposed method can be successfully applied for the determination of pyrethroids in cereals.

4

Development of magnetic solid-phase extraction coupled with dispersive liquid–liquid microextraction method for the simultaneous determination of biphenyl and biphenyl oxide in water Samales

Noori Arezoo Hassan, Rezaee Mohammad, Kazemipour Maryam, Mashayekhi Hossein Ali

Acta Chromatographica

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2019

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Vol. 31, no. 1

1--7

EN

A new and sensitive method, termed magnetic solid phase extraction combined with dispersive liquid–liquid microextracton (MSPE–DLLME), has been developed for the simultaneous determination of biphenyl and biphenyl oxide in water samples. Different parameters influencing the extraction efficiency, including the amount of sorbent, sorption time, type of elution solvent and its volume, type of extraction solvent and its volume, and elution time were optimized. The calibration curves were linear in the range of 0.5–100 μg/L for both of them. The limits of detection (LODs) were achieved, 0.03 μg/L for biphenyl and 0.07 μg/L for biphenyl oxide, respectively. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of biphenyl and biphenyl oxide in sea, river, tap, and water well.

5

Dispersive liquid–liquid microextraction for the simultaneous determination of parent and nitrated polycyclic aromatic hydrocarbons in water samples

Borges B., Melo A., Ferreira I., Mansilha C.

Acta Chromatographica

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2018

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Vol. 30, no. 2

119--126

EN

A new method for simultaneous extraction and quantification of 6 nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) and 16 parent polycyclic aromatic hydrocarbons (PAHs) in water matrices was optimized and validated. The extraction procedure was based on dispersive liquid-liquid microextraction technique, followed by gas chromatography-mass detection. The optimum conditions of extraction (volume of the extraction solvent, dispersive solvents and amount of salt) were selected using central composite design. The best results were found by using 200 μL of acetonitrile as dispersive solvent, 60 μL of chloroform as extraction solvent, and 10% (w/v) NaCl. Excellent linearity was observed in the range of 10–150 ng L−1 with correlation coefficients (r2) ranging between 0.9996 and 0.9999 for nitro-PAHs and in the range of 5–150 ng L−1 with r2 ranging from 0.9998 to 1.000 for PAHs. The limits of detection for the nitro-PAHs studied ranged from 0.82 to 3.37 ng L−1, whereas for PAHs ranged from 0.62 to 3.48 ng L−1. The intra- and inter-day precisions for nitro-PAHs were in the range of 0.45 to 19.54% and 0.43 to 19.62%, respectively, and for PAHs ranged between 0.45 to 17.42% and 0.38 to 18.97%, respectively. The proposed method was successfully applied in analyses of groundwater, sea, rain water and river water, being appropriate for routine analyses.

6

Application of dispersive liquid—liquid microextraction for the analysis of organophosphorus pesticides in Hawthorn (Crataegus pinnatifida var. major) juice samples

Ren Q., Xia T.

Acta Chromatographica

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2016

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Vol. 28, no. 3

403--414

EN

Dispersive liquid–liquid microextraction (DLLME) coupled with gas chromatography equipped with flame photometric detection (GC—FPD) is introduced to extract and determine the fifteen organophosphorus pesticides (OPPs) in hawthorn (Crataegus pinnatifida var. major) juice samples. Some parameters affecting the DLLME efficiency, such as the type and volume of extraction and dispersive solvents, extraction time, and salt concentration, were studied and optimized. The optimized extraction and dispersive solvents are trichloroethane and acetonitrile, respectively. Good linearity was ranged from 0.5 to 100 ng mL−1 with correlation coefficients from 0.9991 to 0.9999. The limits of quantification (LOQs) varied from 0.15 to 0.3 ng mL−1, and the limits of detections (LODs) ranged from 0.05 to 0.1 ng mL−1. The relative standard deviations (RSDs) varied from 1.0% to 2.8% (n = 6) with the relative recoveries in the range of 85.6–119.1%. The method was successfully applied in the determination of OPPs in ten commercial hawthorn juice samples. The chlorpyrifos was detected in one sample.

7

Chemometryczne podejście do optymalizacji dyspersyjnej mikroekstrakcji w układzie ciecz-ciecz (DLLME), jako metody przygotowania próbek do rozdzielania i oznaczania krezoli w ściekach rafineryjnych

Makoś P., Boczkaj G.

Camera Separatoria

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2014

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Vol. 6, No. 2

65--71

PL

W pracy przedstawiono procedurę optymalizacji dyspersyjnej mikroekstrakcji w układzie ciecz-ciecz (DLLME), z zastosowaniem frakcyjnych planów czynnikowych tj. planu Placketta-Burman'a oraz centralnego planu kompozycyjnego. Zdefiniowano parametry mające istotny wpływ na efektywność ekstrakcji krezoli i dla nich przeprowadzono procedurę optymalizacyjną, w wyniku której wyznaczono wartości optymalne parametrów w tym pH 6 oraz objętość rozpuszczalnika dyspergującego wynoszącą 0,4 mL.

EN

This paper present the procedurę to optimize dispersive liquid-liquid micro-extraction (DLLME), using fractional factorial plans i.e. Plackett-Burman design and central composite design. The parameters affecting the effidency ofextraction were determined and for them the optimum conditions were established, by which determined the optimum values of parameters including pH 6 and volume of disperser solvent equal 0,4 mL.

8

Gas chromatographic determination of parabens after in-situ derivatization and dispersive liquid-liquid microextraction

Prichodko A, Janenaite E, Smitiene V, Vickackaite V.

Acta Chromatographica

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2012

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Vol. 24, no. 4

589--601

EN

Dispersive liquid-liquid microextraction in combination with an in situ derivatization is suggested for parabens sampling and preconcentration. The derivatization was carried out with acetic anhydride under alkaline conditions maintained using di-potassium hydrogen phosphate. The effects of an extraction solvent type, extraction and disperser solvents volume, extraction time, and ionic strength of the solution on the extraction efficiency were investigated. Chlorobenzene containing n-hexadecane as internal standard was used as an extracting solvent and acetone was used as a disperser solvent. The calibration graphs were linear up to 10 mg mL-1, correlation coefficients were 0.997–0.999, enrichment factors were from 70 for methylparaben to 210 for butylparaben, and detection limits were 22, 4.2, 3.3, and 2.5 µg L−1 for methylparaben, ethylparaben, propylparaben, and butylparaben, respectively. Repeatabilities of the results were acceptable with relative standard deviations up to 11%. A possibility to apply the proposed method for parabens determination in water samples was demonstrated.

9

Determination of nalidixic acid using dispersive liquid-liquid microextraction followed by HPLC-UV

Daneshfar A, Lotfi H. J, Khezeli T

Acta Chromatographica

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2011

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Vol. 23, no. 4

567--577

EN

A fast, simple, and sensitive sample preparation procedure based on dispersive liquid-liquid microextraction (DLLME) followed by high-performance liquid chromatography and ultraviolet (HPLC-UV) detection was developed for the determination of nalidixic acid in a human urine sample. A mixture of extraction solvent (35 μL carbon tetrachloride) and disperser solvent (1.0 mL acetonitrile) were rapidly injected into an aqueous sample (5.0 mL) for the formation of cloudy solution; the analyte in the sample was extracted into the fine droplets of carbon tetrachloride. After extraction, phase separation was performed by centrifugation and the enriched analyte in the sedimented phase was determined by HPLC-UV. The influence of several important parameters on extraction efficiency of nalidixic acid was evaluated. Under optimized experimental conditions, the calibration graph was linear in the concentration range of 1–800 μg L-1 with the coefficient of determination being 0.9994. The limits of detection and quantification were 0.2 and 0.7 μg L-1, respectively. The relative standard deviations (RSDs) and accuracies were in the range of 1.1–8.7% and 92.7–104.9%, respectively. This procedure was successfully applied to the determination of nalidixic acid in spiked urine samples with satisfactory results. The relative recoveries of urine samples ranged from 103.1% to 105.1%, with RSDs varying from 0.8% to 2.4%.